1. Field of the Invention
This invention generally relates to electrical switching devices and more particularly to a terminal structure that can be used advantageously with such switching devices.
2. Description of Related Art
A number of electrical switching devices comprise two or more terminals for connection in an electrical circuit and a bridging or other movable contact means for making and breaking an electrical connection between the terminals. Actuator means shift the movable contact means between open and closed circuit positions.
As shown in U.S. Pat. No. 30,273 reissued May 13, 1980, such switching devices include a common terminal normally comprising an external terminal mounted to the exterior of a housing and a U-shaped internal contact on the inside of the housing. A rivet extends through the housing and clamps the external terminal and internal central contact together A bridging contact pivots about the U-shaped central contact under the influence of an actuator. In this particular patent the actuator means comprises a rocker actuator that rotates about a pivot pin and that contains a spring mounted plunger for allowing the bridging contact to spring to an open position in one orientation of the rocker and to overcome the spring bias and close the contact in another position of the rocker.
In this and other similar switch configurations, this common terminal structure comprises three discrete pieces, namely: an external terminal, an internal contact and a rivet. Further the internal contact extends along an axis that is transverse to the plane of travel for the actuator means. It becomes difficult and tedious to assemble this contact, particularly if component orientation is critical. A switch housing may require special molded recesses for aligning the internal contact and external terminal properly during a riveting operation. In smaller switches, the entire riveting operation can become difficult even without a component alignment requirement.
It also has been proposed to combine two of the three components in a subassembly. For example, in some switching devices the external terminal and a rivet or stud become a subassembly that is inserted into the switch housing. The internal contact is positioned over an extension of the rivet or stud inside the housing. A riveting or corresponding peening operation then drives the rivet or stud onto the internal contact to complete the operation. However, the number of operations are essentially the same as required with three discrete components. Moreover, it is still difficult to locate the external terminal and the internal contact during a peening or riveting operation.